第十五章 诊断试验设计与资料分析的 Stata 实现本章使用的 Stata 命令诊断试验diagti #a #b #c #d （见 Stata7 附加程序）表 15-3 两个医生诊断胆结石的一致性分析乙医生甲医生胆结石 正常合计胆结石a (86)b (42 )a+b (R1,128)正常c (34)d (224)c+d (R2,258)合计a+c (C1,120)b+d (C2,266)N (386)Stata 命令为diagti 86 42 34 224结果为： True | disease | Test result status | Neg. Pos. | Total-----------+----------------------+---------- Normal | 224 34 | 258 Abnormal | 42 86 | 128 -----------+----------------------+---------- Total | 266 120 | 386 [95% Confidence Interval]---------------------------------------------------------------------------Prevalence Pr(A) 33% 28% 38.1%---------------------------------------------------------------------------Sensitivity Pr(+|A) 67.2% 58.3% 75.2%Specificity Pr(-|N) 86.8% 82.1% 90.7%ROC area (Sens. + Spec.)/2 .77 .724 .816 ---------------------------------------------------------------------------Likelihood ratio (+) Pr(+|A)/Pr(+|N) 5.1 3.64 7.13 Likelihood ratio (-) Pr(-|A)/Pr(-|N) .378 .294 .486 Odds ratio LR(+)/LR(-) 13.5 8.07 22.6 Positive predictive value Pr(A|+) 71.7% 62.7% 79.5% Negative predictive value Pr(N|-) 84.2% 79.3% 88.4% ---------------------------------------------------------------------------敏感度为 67.2％，特异度为 86.6％。
